2013-03-14_REPORT - C1981010 (7)

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4.0 SURFACE WATER Trapper Mine monitored one stream site and nineteen active NPDES discharge sites during 2012. The stream site Flume Gulch (S -1) was sampled during June 2012 to characterize spring flows at this location. Flow was observed at NPDES sites 001, 002, 005, 011, 013, 014, 015, 017, 018, 020 and 021 in 2012. Sites 005, 014, 015 and 018 had flow only one time during 2012. Baseline stream site East Pyeatt (S3) is also NPDES site 011. Sites were monitored weekly throughout the year. Sites NPDES 008, 012, 016, 019, 022, 023 and 024 did not discharge during 2012. Maps No. 2 -1 through 2 -3 show the locations of these surface -water sites. 4.1 SURFACE -WATER FLOW The 2012 flow data tabulated in Appendix C in Table C -1 represents instantaneous measurements associated with NPDES water - quality sampling. Surface runoff was less in 2012 at the Trapper Mine with the precipitation being below average except for some of the peaks in March and April. Figures C -1 through C-4 present the instantaneous flow versus time for the Trapper NPDES sites for 2012. There was flow during each of the weekly samples of 2012 at NPDES 001 except for most of the July and August samples. The high flow during sampling was 1687 gpm on March 6. The peak flow during sampling of NPDES 002 was on April 13, with a rate of 743 gpm. Surface flow at NPDES 011 was observed during most of the year with a peak of 286 gpm on March 13 and NPDES 017 during two weeks (see Figure C -2). Figure C -3 shows that NPDES 013 and 018 sites had two and one flow events in 2012 respectively. Figure C-4 shows that low flows occurred at NPDES Site 020 up to mid -March with some very low flows the remainder of the year. This figure also shows that a peak flow of 2309 gpm was observed at NPDS Site 021 in 2012. A small flow Trapper Mining Company 4 -1 2012 Annual Report